Arcesilaus (316/5–241/0 BC) was a Greek philosopher.

Arcesilaus or Arkesilaos (/ˌɑːrsɛsɪˈleɪ.əs/; Ancient Greek: Ἀρκεσίλαος) is a Greek name (Arcesilaus is the Latin spelling), which may also refer to:

People

Four Kings of Cyrene

• Arcesilaus I of Cyrene (fl. 7th–6th centuries BC)
• Arcesilaus II of Cyrene (fl. 6th century BC)
• Arcesilaus III of Cyrene (fl. 6th century BC)
• Arcesilaus IV of Cyrene (fl. 5th century BC)

Others

• Arcesilaus (mythology), one of the Greek leaders in the Trojan War
• Arcesilaus (satrap) (fl. 4th century BC), one of Alexander the Great's generals
• Arcesilaus (consul) (fl. 3rd century BC), Roman senator appointed consul in AD 267
• Arcesilaus (sculptor) (fl. 1st century), Roman sculptor

Astronomy

• 20961 Arkesilaos, an asteroid